Description: The Cell Biology Program consists of 16 members whose major objective is to understand the signal mechanisms that control cell proliferation and differentiation and study the derangement of these mechanisms in cancer. The goal is to provide a framework for identification and neutralization of the alterations underlying cancerous growth. The Cell Biology Program underwent rapid growth just prior to the present grant period. The recruitment of six program members at that time significantly increased the size of the program. The current period has had as its objectives (1) to integrate and develop the careers of those newer members, (2) to recruit one new member of the program (Dr. Robert Fisher), and (3) to co-recruit the Director of the Human Genetics Program (Dr. Lucio Luzzatto). The decision to recruit Dr. Robert Fisher was made by the program Executive Committee, which consists of senior faculty. This committee meets bi-monthly to discuss the program and assess the research direction and productivity of junior faculty and evaluate them for promotion. The Executive Committee recruited Dr. Fisher for his expertise as a biochemist studying the cell cycle, an area of emphasis in this program. Program members receive a total of $1.6 million in direct costs from National Science Foundation (NSF), American Cancer Society (ACS), other NIH institutes, and the NCI. There are thirteen grants, including two Breast Cancer SPORE sub-projects, two grants from the NSF, three from the ACS, a sub-project on a U-19, and five R01-type grants, including a MERIT award to Dr. Massague. The mechanisms for promoting interaction includes a Chairman-sponsored, weekly, "Cell Regulation Work-in-Progress" seminar series. This involves approximately 30 of the Center?s basic and clinical investigators from various programs, including the entire faculty of this program. In addition, the Chairman meets with each faculty member yearly to assess progress. The program members use multiple core facilities in their research. Developmental funds were used to provide start-up funding for the laboratories of two investigators during the current cycle, both of whom are now funded.